1. Field of The Invention
The present invention relates to an inner structure of an endoscope and more particularly to an inner structure of an operation section which includes a forceps opening for guiding a medical treatment means such as a biopsy forceps.
2. Description of The Related Art
FIG. 5 shows an inner structure of a conventional endoscope. As shown in the drawing, an operation section 3 includes a forceps opening 1 which communicates with the end of an insertion part 5 which is inserted into the interior of a human body via a pipe 2 and a tube 4. The pipe 2 and the tube 4 are connected to each other by a first connecting member 6 which is cylindrical and has a convex(T)-shape in cross section, and the second connecting member 7. The first connecting member 6 is secured to the end of the pipe 2. The tube 4 is made to pass through the second connecting member 7.
In order that the pipe 2 and the tube 4 are connected to each other, the second connecting member 7 is retracted in such a manner to contact with a joint 9 as shown in FIG. 6. Then, the end of the tube 4 is coupled to a projected portion 6A of the first connecting member 6. Then, the second connecting member 7 is moved toward the first connecting member 6 along the tube 4, and the first connecting member 6 is screwed in the second connecting member 7. The tube 4 is held between the projected portion of the first connecting member 6 and a ring 7A of the second connecting member 7. As a result, the pipe 2 and the tube 4 are connected to each other. The above-described connecting process is generally carried out by handwork at the time of manufacturing.
The insertion part 5 is connected to the operation section 3 by the joint 9. An inner space 9A is formed inside the joint 9. The above-mentioned tube 4, an image bundle in the case of a fiber scope, and an electric cable in an electronic endoscope, etc. pass through the inner space 9A.
In the case of the conventional structure for the operation section of an endoscope, a space for connecting the pipe 2 to the tube 4 is restricted by a length L1 from a right end 7B of the second connecting member 7 of which left end is in contact with an end surface 9B of the joint 9, to a left end of the projected portion 6A as shown in FIG. 6.
Under the conventional condition, the length L1 is too short to perform the connecting process easily. If the length L1 is designed longer so as to secure a lager space which is required for easy connecting process, the operation section should be longer. That is, the forceps opening side of the operation section should be longer in particular, as a result, the endoscope has a spoiled overall balance which causes a difficult operation thereof. As a result, there is a disadvantage in that the connecting process has to be carried out in an extremely small space when the conventional endoscope is assembled.